The present invention relates to a method for making silicone gels including elastomers, potting compounds and coating formulations, by subjecting a curable silicone mixture to ultrasonic energy, where the curable silicone mixture comprises a vinyl silicone, a silicone hydride siloxane and an effective amount of a platinum group metal catalyst.
Prior to the present invention, as shown by Lewis et al, U.S. Pat. No. 5,015,691, organopolysiloxane compositions curable by a platinum catalyzed hydrosilylation addition reaction, were generally cured by the use of heat. However, Boudjouk, U.S. Pat. No. 4,447,633 found that if ultrasonic energy were used, the addition of a silane having silanic hydrogen to an olefinically unsaturated compound such as 1-hexene or styrene could be effected. A supported platinum metal catalyst was used. The platinum catalyst preferred by Boudjouk was a platinum metal catalyst having a high surface area, such as a finely divided metal catalyst on a carrier such as carbon particles. Attempts to duplicate Boudjouk results by using ultrasonic energy to effect the hydrosilylation of an aliphatic compound to a silicon hydride, using an unsupported or homogeneous platinum catalyst, such as a platinum catalyst soluble in an organic solvent, for example the platinum complex shown by Karstedt, U.S. Pat. No. 3,775,452, were unsuccessful.